they're gathering in washington. japan's chief negotiator from the foreign ministry, shinsuke sugiyama, flew out on tuesday. leaders in tokyo pushed for these in-depth talks. analysts from the three countries have already been sharing key information on north korea. south korea's chief negotiator, lim sung-nam, also traveled to the u.s. capital. >> translator: i would like to step up diplomatic efforts with the united states in a bid to prevent north korea from launching a missile. >> sugiyama and lim will be meeting up with glynn davies, the u.s. special representative on north korea. the three senior diplomats are expected to demand north korea exercise restraint and will likely refer to a u.n. security council resolution banning such activity. they're also expected to discuss plans of action in case the launch happens. the diplomats are likely to request the security council to issue a strong condemnation. >>> police in central japan are trying to find some clues as to why a highway tunnel collapsed. they've searc